Cryptography is the practice and study of logical means used to achieve information confidentiality, integrity and authenticity. It covers, among other things, encryption (making some data unreadable except for those who know a given secret element, called a key), data hashing (in particular for ...

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X509Certificate - How to set validation Policies?

I have an X509Certificate (say Certificate-A) for signing purpose. While validating this certificate, I have to check its path with Intermediate & Root certificate which I have implemented fully. ...
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1answer
47 views

Hashing password for secure storage (generating salt)

I wanted to check if the following means of generating a hash for storage of a password was secure. I have an username and password combo. In order to generate a secure hash, I am doing the ...
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4answers
467 views

Demonstration of how security through obscurity fails to work

I need to demonstrate that security through obscurity fails twice in the following scenario. I've a secret KEY. User A gets MessageX = SecretTransformation(KEY, SecretValue1); User B gets MessageY ...
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1answer
88 views

RSA vs ECDSA for VANET Security

I am doing a project on Vehicular Ad-Hoc Network Security (VANET). The proposed scheme uses electronic signature as a means to authenticating the nodes. Most of the research papers I read suggested ...
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3answers
95 views

Decrypting Engima messages

Not really computer related, but I hope someone has the answer. How do people decode messages from an Enigma machine? I understand that if you knew the rotors, rotor positions, and plugboard the ...
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0answers
42 views

Brute-Force/Dictionary attack against encypted file using PBKDF2 key derivation

I have been following this very useful post by Thomas. My use case is slightly different. I am developing a mobile application which requires some sensitive data to be stored on the device in a SQLite ...
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2answers
209 views

Is crypto.js vulnerable to heartbleed attack? [duplicate]

We are using 'crypto.js' in our application. Since 'crypto.js' uses open SSL ,are we vulnerable to heartbleeding attack? If yes, what can we do to prevent it?
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2answers
78 views

Cryptosytem Question

A file is encrypted and placed on a secure FTP server. An MD5 hash is taken of the file and also placed on the FTP server. A userlogs in to the server and downloads both files, however, the hash fails ...
34
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6answers
2k views

Why is HTTPS not the default protocol?

Why is HTTP still commonly used, instead what I would believe much more secure HTTPS?
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1answer
53 views

Avoiding Replay Attacks on Lightweight Channel

I'm in the process of building a network of small devices (ARM microcontrollers with something like nRF24L01 connectivity). The controllers will be receiving commands from a central system over these ...
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1answer
61 views

Cryptographic Hash function [closed]

How can I implement a cryptographic hash function using the block cipher? I was wondering whether I can use AES in cipher block chaining mode to achieve this.
3
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1answer
55 views

Is there an actual use for OpenPGP authentication keys?

The OpenPGP specification (RFC 4880) describes, page 34, the different capabilities that an OpenPGP key may have; including: 0x20 - This key may be used for authentication. In GnuPG, one of the ...
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5answers
18k views

Asymmetric vs Symmetric Encryption

I am currently taking a principles of information security class. While talking about different encryption methods a large number of my classmates seem to believe that Asymmetric Encryption is better ...
4
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1answer
119 views

How would you know a certificate/private key if you extracted it from RAM? Or would you?

Related to, of course, the heartbleed vulnerability, I've been reading the news about the worst case scenario for this attack being the extraction of the SSL private key, because, of course, this ...
13
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7answers
673 views

Online Government Elections System - Is it possible?

I am from Bulgaria and currently some groups here are promoting the idea of referendum among the people, about the possibility for establishing a system for ONLINE GOVERNMENT ELECTIONS. The idea is ...
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1answer
136 views

How does CryptoDefense ransomware encrypt large data with a (relatively) small RSA key?

I recently encountered some news about the recently new Ransomware called CryptoDefense: it uses RSA 2048 to encrypt your valuables and offers the private key for a price. (It's already been solved ...
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1answer
72 views

Is my AES/CTR/RIPEMD encryption correctly implemented?

Below is my encryption implementation in PHP. It's based on mcrypt, and uses AES-128 in CTR mode along with a RIPEMD-128 HMAC for integrity checking. For brevity, I've inlined the functions for ...
4
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1answer
57 views

Recommended symmetric key usage period

Let's assume that there are two nodes A and B connected over a network. Both have a single pre-shared symmetric key (e.g., AES-128) and exchange messages. What is the recommended period, until the ...
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1answer
53 views

What is default mode for AES encryption [closed]

What will be the default mode for AES encryption if we don't use any specific mode like ECB, CBC, OFB, CTR, etc. and just carry out the encryption without specifying any AES encryption mode.
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2answers
90 views

How can I analyze password recovery tokens?

All websites that support authenticated user interactions have a password recovery feature. Usually they will email the password reset link through which you can easily recover your account by typing ...
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1answer
57 views

Get PGP Private Key from RAM analysis RSAKeyFind

For an experiment, I'm trying to open a 2048-bit RSA encrypted mail on a image. Using this fresh image, I made a memory dump and analysed the dump for RSA keys. Now, several RSA keys have been ...
21
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3answers
2k views

Is there any advantage to splitting a password?

I've been reading about the LANMAN (LM) hash and I'm curious about a particular part of the algorithm. The LM hash is computed as follows: The user’s ASCII password is converted to uppercase. ...
2
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1answer
145 views

PFS incentive during IKE Phase 2

I'm trying to see the actual point in implementing Perfect Forward Secrecy during Internet Key Exchange Phase 2, if it had already been used during Phase 1. Quoting the IKEv2 RFC: RFC 5596 ...
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0answers
50 views

Utilizing PBKDF2 With OpenSSL crypto library [migrated]

I want to utilize the PBKDF2 algorithm with SHA1 HMAC (based on this answer). How can I utilize this through the crypto library? I started by looking at man openssl, but the openssl passwd command ...
3
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2answers
109 views

What does the “period” of a random number generator measure?

What is "period" in the context of pseudo-random number generators? For example when someone says "The Mersenne Twister has a 2^19337−1 period" what does it mean? I would appreciate a simple as ...
22
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5answers
2k views

Why is Bruce Schneier recommending symmetric crypto over public key crypto

I just read the article written by Bruce Schneier, the crypto guru. In the article, he says : Prefer symmetric cryptography over public-key cryptography. But, he doesn't shed any light as to ...
2
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0answers
35 views

Snapchat clone: How do I secure pre-downloaded notifications so that they cannot be opened outside of the app? [duplicate]

Say I'm making a snapchat clone app for Android and iOS. Let's say that I get a snapchat from Baz. I want to pre-download the audio for this snapchat. However, as the developer, I want to secure this ...
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2answers
30 views

What are some examples of a block cipher's versatility over a stream cipher?

I understand that a block cipher can be made to act like a stream cipher at the cost of "losing versatility" of the block cipher for the sake of performance. I don't understand what I'd be losing. ...
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1answer
59 views

Current Encryption Algorithms? [closed]

What are some encryption algorithms that are currently in use by secure websites, by operating systems, or by Secure USB thumb drive manufacturers. I am trying to do research on differences in speed ...
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4answers
136 views

How do big companies and wealthy people secure their information? And how can I secure mine?

I've recently had some success and traffic increase with an online business I own and due to that someone has hacked my domain email and twitter accounts. My bank password is the same and I just ...
94
votes
7answers
6k views

Why are salted hashes more secure?

I know there are many discussions on salted hashes, and I understand that the purpose is to make it impossible to build a rainbow table of all possible hashes (generally up to 7 characters). My ...
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1answer
45 views

MySQL authentication, how to pad the 20-byte salt

Im authenticating with a mysql server with the authentication method listed here. I observed the salt and hash using wireshark, and I know the password, but I am having trouble reproducing the hash I ...
2
votes
1answer
62 views

Better than brute-force way to find the “lowest” sha1 hash?

While pointing out a SQL injection flaw on another question, I was able to show that an arbitrary sha1 hash could be inserted into a query such that it would be taken for a real hash, and was ...
1
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1answer
50 views

Need help designing an encryption workflow

Background: I'm building a .NET application, a very small part of this application allows for users to communicate with a third party application. I am designing this aspect. The third party simply ...
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0answers
38 views

Is it possible to produce incorrect Metadata?

There is an app on xposed installer called XPrivacy for android that let's you decide what information you want your device to give a specific app and for information you don't want to give it ...
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3answers
2k views

What specific padding weakness does OAEP address in RSA?

It's been recommended to use OAEP when padding messages to be encrypted via RSA, to prevent known plain text attacks. Can someone elaborate this in better detail? I'd specifically like to know the ...
7
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2answers
2k views

SSL Session resumption and IDs

Some sites, as seen in the report for www.mbank.com.pl [ssllabs.com] or report for aliorbank.pl [ssllabs.com] do not support "Session resumption", either because IDs are assigned but not accepted ...
2
votes
1answer
121 views

Should generating gpg keys ever result in an identical key to an older key?

I recently had a situation where I lost an old private key (write error; realized this too late). In regenerating keys and replacing the public keys on various sites, I noticed that the public keys ...
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1answer
91 views

Requiring 2 keys to access a content

I need to use an external service that can only be accessed by password. I don't like the idea of storing the plaintext password on the server, but AFAIK there's not much I can do. Considering this ...
2
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1answer
58 views

Is there a widely used protocol which builds on AES/GCM, and defines serialization formats of A, IV, C and T together?

note: Title edited to make the answer more useful to a wider audience I'm reading source code for encrypting files with AES GCM and see the following binary output. AdditionalAuthData IV ...
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3answers
319 views

Would this kind of encryption be good at anything?

I have put much thought into this very simple algorithm and I have no clue if it was thought before... But I think it should have. I also know nothing about other encryption algorithms so I can't tell ...
0
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2answers
87 views

If P=NP, what is still cryptographically secure? [duplicate]

I know, I know - "If P=NP" is a really large, high-impact assumption. But this is a hypothetical. I mean, clearly RSA (and similar methods of obfuscation) would likely become totally irrelevant - or ...
0
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2answers
198 views

Google's usage of RC4

I was reading about Google's usage of RC4 and an answer on stackexchange website stated the following: I know Google uses RC4 for most of its services, and this is the reason one shouldn't keep ...
6
votes
8answers
1k views

Does truncating the cryptographic hash make it impossible to crack?

I store password hashes in their full value for example, $h = sha256('foo') outputs 64 characters: 2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae I store that directly in the ...
15
votes
3answers
400 views

Storing passwords in reversible form - a genuine use-case

What's wrong with you, you crazy fool, you're not supposed to be able to retrieve a password in plain text! I know. Hear me out. Assume I've got a service that's similar to Mint.com. For those that ...
12
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4answers
553 views

Why are there few (none?) easy to use encryption libraries?

If I search stack overflow for how to safely encrypt data, one of the first hits is someone's custom encryption scheme. I've seen several similar questions on this site, and in general they are all ...
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3answers
98 views

How encryption/decryption works when one generate random key?

I am new to this and want to ask a basic question.Suppose I used my password (say "ABC123") to generate a key using PBKDF2 algorithm (or any such algorithm).For encrypting a file I'll input my ...
6
votes
6answers
808 views

Testing a hardware random number generator

The Raspberry Pi has a built in hardware random number generator but there doesn't appear to be any public documentation on the hardware, and even if there were it would be questionable (what company ...
151
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8answers
63k views

Why not use larger cipher keys?

RSA Security commonly uses keys of sizes 1024-bit, 2048-bit or even 3072-bit. And most Symmetric algorithms only between 112-bit and 256-bit. I do realize that the current keys are secure enough for ...
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1answer
48 views

Root certifcate from an CA company which can be encrpyted by SoftHSM

Does anybody know a CA company which allows me to put the bought CA certficate inside SoftHSM (the same as an HSM but without any hardware, it is pure software)? Is it hard to work with the PKCS11 ...